What happens when whitetail and mule deer meet up?
Longstanding studies by Texas Parks & Wildlife Department officials show some interesting dynamics including hybridization.
“Research indicates that mule deer in Texas prefer a brush canopy cover of 40 percent or less, while white-tailed deer numbers increase dramatically in areas with a brush canopy exceeding 50 percent. The greatest white-tailed deer numbers were found in areas that consisted of about two-thirds brush cover. When the two species occupy the same area, they often are segregated — muleys preferring the high, rougher canyons and open hillsides and white-tailed deer occupying the brushy draws and lowlands.”
“Where mule deer and white-tailed deer coexist, interbreeding does occur. The long-term effects are unknown, and for most areas, the extent of hybridization is not known. The highest incidence of hybridization in the Trans-Pecos occurs in the eastern part of the region where high populations of mule deer and white-tailed deer coexist. It has been estimated that up to 15 percent of deer may be hybrids where both species occupy the same range. DNA sequencing techniques were used to determine the extent of hybridization in the Panhandle (Donley County) where the ranges of both species overlap. Results indicated a hybridization frequency of eight percent. Antler characteristics, tail coloration and ear length are not reliable in recognizing hybrids. Hybrids can be identified by the length of the metatarsal gland that is located on the outside of the rear leg between the hock and the hoof. It typically will measure about 3 /4 inch long in whitetails and about 4 inches long in mule deer.”
“The metatarsal gland of hybrids is intermediate in length, measuring about two inches long. It has been theorized that occurrences of hybridization are initiated by white-tailed bucks, but interbreeding also can occur between mule deer bucks and white-tailed does. Hybrids appear to have at least a limited degree of fertility. Hybridization is a concern to managers who see it as a threat to their mule deer herd. Habitat management is the most effective, long-term means for maintaining the integrity of the mule deer population. Habitat enhancement practices that reduce the amount of brush cover to 40 percent or less may improve the value of habitat for mule deer and discourage the encroachment of white-tailed deer. Liberal harvest of white-tailed deer through legal means is an additional management option that can help favor a mule deer herd where both species coexist.”
Whitetail numbers have reached historic highs and mule deer are on the decline in many areas.
It will be interesting to look back into areas where muleys and whitetails mix and see how things are in 20 years.